Coal used to be burned everywhere in homes and industries. What happened to all the ash produced? Pittsburgh alone must have generated mountains of the stuff. Are there vast ash deposits somewhere, or was a use found for it?
I know at one point it was used to grit icy roads to improve traction. The darkness of the coal ash also helped melt the snow and ice by absorbing heat from sunlight that would otherwise be reflected.
I used to work in a power plant many years ago. We sold all of the fly ash that we produced.
In addition to being used to melt ice, it is also used to make concrete, and is used to make certain types of roof tiles, and is used as a filler in certain types of wood and plastic products.
Yeah, and sometimes they cause a heap of trouble.
Hence the term “cinder block”. Note that what ash ultimately is is “concentrated heavy stuff that wasn’t carbon”, which means that, among other things, you’re concentrating any radioactive material that may have been in the coal, and old concrete walls will often set off a Geiger counter for this reason.
And while it is used for practical things like concrete and road grit, there’s still a lot more of it produced than that, and it ends up in huge dumping grounds. Which sometimes have catastrophic spills.
coal ash was also a major component of the fill used to extend many coastal cities. A large portion of the present-day shoreline of Manhattan is landfill, and so is all the Back Bay of Boston. The fill dumped here was a mixture of ash, compost, dirt, and other trash. In New York, for example, they recently found the hull of an 18th-century trading vessel in the excavation of Ground Zero. A large portion of Lower Manhattan didn’t exist when the Dutch bought it.
Some goes into ash ponds, some goes to landfills (dry ash handling), and some gets sold to make the products discussed by earlier posters.
http://www.flyash.info/2009/Hardin-WOCA2009-plenary.pdf (warning: pdf)
Fly ash - Wikipedia
There are quite a few reprocessors of flyash now. Here is one company that processes ash on-site from coal plants. They have some video’s posted of the end products and uses:
http://www.sefagroup.com/company_info/company_info.html